Effect of puerarin on the expression of NMU, NPY, and POMC genes in the hypothalamus.

The hypothalamus is an important component of the nervous system, and neuropeptide Y (NPY), proopiomelanocortin (POMC), and neuromedin U (NMU) are key players in physiological regulation. Puerarin is important for nerve regulation. We investigated the effect of puerarin on the expression of NMU, NPY, and POMC genes in the hypothalamus. The results showed that the puerarin low-dose group and the other groups were significantly different (P < 0.05). However, there was no significant difference in NMU, POMC, and NPY among the groups.

Attenuated mRNA expression of lipid metabolism genes in primary hepatocytes following lipopolysaccharide treatment in dairy cows.

The influence of ruminal acidosis on ruminal microbiology and metabolite production has received considerable attention, but little is known regarding the systemic manifestations that arise from ruminal acidosis. Lipopolysaccharide (LPS) is released in the gastrointestinal tract upon ingestion of high-grain or high-fat diets, and it has been implicated in the etiology of multiple energy- and lipid-related metabolic disturbances in ruminants. The liver plays a crucial role in the acute phase response to intruding pathogens. The effect of blood LPS in subacute ruminal acidosis on lipid metabolism in the liver has not been established. In this study, cell cultures were photographed using an inverted microscope. We observed that hepatocytes changed their morphologies from irregular triangle to circular (contraction) shapes; the number of contracted cells increased with the increasing LPS doses. This suggests that LPS can promote cell contraction and take off the wall, ultimately leading to cell apoptosis. With changes in LPS exposure, hepatocyte number also changes. We explored lipid metabolism in the liver using quantitative reverse transcription-polymerase chain reaction to detect the expression of key lipid metabolism enzymes in hepatocytes. We found that Toll-like receptor 4 signaling pathway mediated by LPS could attenuate mRNA expression of fatty acid synthesis genes and increase the expression of fatty acid transport genes in primary hepatocytes following LPS treatment in dairy cows.

Effects of lipopolysaccharide on the stearoyl-coenzyme A desaturase mRNA level in bovine primary hepatic cells.

This study aimed to compare the effects of lipopolysaccharide (LPS) on stearoyl-coenzyme A desaturase (SCD) gene expression in mouse primary hepatic cells. To obtain sufficient total RNA, primary hepatic cells were plated on 6-cm diameter-type collagen 1-coated dishes (1 x 106 cells per dish). The test was divided into 6 groups with 6 replications per group. The 6 groups were treated with the following volumes of LPS (0.1 mg/mL): 0, 1, 1.5, 2, 4, and 8 µL. The cells were cultured for 24 h, and the total RNA was extracted from samples. Reverse transcription polymerase chain reaction was used to analyze SCD mRNA levels. With increasing LPS amounts, the SCD mRNA expression first decreased and then increased slightly; the expression was the lowest in the 2-µL LPS condition. The SCD mRNA levels from the 4- and 8-µL LPS conditions were slightly higher than that from the 2-µL LPS condition, but the difference was not significant (P > 0.05). The SCD mRNA level from the 2-µL LPS condition was obviously lower than that from the 0-, 1-, and 1.5-µL LPS condition, and the differences were significant (P < 0.05), and the SCD mRNA levels from the 0-, 1-, and 1.5-µL LPS conditions were not significantly different (P > 0.05). The SCD mRNA levels from the 4- and 8-µL LPS conditions were obviously lower than those from the 0- and 1-µL LPS conditions, and the differences were significant (P < 0.05).

Isolation and identification of bovine primary hepatocytes.

The liver is a unique organ that is endowed with a plethora of specialized functions. Most of its functional traits are controlled by hepatocytes. Primary hepatocytes have been used widely in in vitro models to understand the biological processes occurring in the liver. There are a number of methods used to separate hepatocytes, but the cell activity and purity are much lower in this condition. On the basis of previous research, in this study, the two-step collagenase perfusion technique was used for isolating hepatocytes. The key proteins of hepatocytes, cytokeratin-18 (CK-18) and albumin (ALB), were used to identify cells, and their contents were evaluated by immunohistochemistry and Western blotting. The results showed that the isolated hepatocytes comprised more than 96% of the corresponding protein volume stability. Therefore, this method was demonstrated to be reliable for identifying hepatocytes.

Leptin mRNA expression in the rat mammary gland at different activation stages.

Leptin is expressed in various tissues, suggesting that this protein is effective not only at the central nervous system level, but also peripherically. Recent studies have shown leptin production by other tissues, including the placenta, stomach, and mammary tissues, but there is no information available concerning expression levels of leptin in the rat mammary gland at different activation stages. We used semi-quantitative RT-PCR to investigate leptin mRNA expression levels in the rat mammary gland at different activity stages. Rat mammary gland samples were collected from virgin females and on days 6, 12, 18 of pregnancy and of lactation (six rats per group). The expression levels of leptin mRNA were measured by semi-quantitative RT-PCR, with ß-actin as an internal control. Leptin mRNA was highly expressed in virgin rat mammary glands (leptin(IOD)/ß-actin(IOD) = 1.60). It decreased gradually during pregnancy, being lowest at 18 days of pregnancy, when the levels were significantly lower than in virgin mammary tissue. Leptin mRNA increased slightly during lactation, but the difference was not significant. By day 18 of lactation, expression levels of leptin mRNA reached the same values as in virgin mammary tissue (leptin(IOD)/ß-actin(IOD) = 1.65). Based on these results, we suggest that leptin has an important regulation role in rat mammary gland activation.